Floating electromagnetic field generator system and method of controlling the same

ABSTRACT

Floating electromagnetic field generator systems and methods are provided. The system comprises a surgical bed portion. The system also comprises a brace component disposed within the surgical bed portion. Additionally, the system comprises a first arm that is attached to the brace component. The first arm is positioned adjacent to the surgical bed portion. Additionally, the first arm has at least one field generator coil embedded therein. The system also comprises a second arm that is attached to the brace component. The second arm is positioned adjacent to the surgical bed portion. Additionally, the second arm has at least one field generator coil embedded therein. The second arm is positioned parallel to the first arm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/320,193 entitled “Floating Electromagnetic FieldGenerator System and Method of Controlling the Same,” filed Apr. 8,2016, the disclosure of which is hereby incorporated by reference in itsentirety.

BACKGROUND Field of the Invention

The field of the present application pertains to medical devices. Moreparticularly, the field of the invention pertains to an electromagnetictracking surgical system and a method of controlling the same.

Description of the Related Art

A surgical procedure may be performed on a patient using one or moresurgical tools when the patient is placed on a surgical bed. Thesurgical tools may include endoscopes, catheters, ureteroscopes, orother similar devices. Endoscopy is a widely-used, minimally invasivetechnique for both imaging and delivering therapeutics to anatomicallocations within the human body. Typically a flexible endoscope is usedto deliver tools to an operative site inside the body—e.g., throughsmall incisions or a natural orifice in the body—where a surgicalprocedure is to be performed. Endoscopes may have imaging, lighting andsteering capabilities at the distal end of a flexible shaft enablingnavigation of non-linear lumens or pathways.

SUMMARY

Examples of a floating electromagnetic (EM) field generator system areprovided. The floating EM field generator system may be used to supportand/or develop arms disposed next to a surgical bed so as to preventdistortion of a field generator system due to bending of the surgicalbed.

The placement of field generator coils within or adjacent to a surgicalbed may be used for tracking surgical tools. In particular, when asensor associated with a surgical tool interacts with an EM fieldgenerated by the field generator coils, the interactions may be measuredto determine a location of the surgical tool.

However, the determination of a location of the surgical tool is basedon a calibration of the field generator coils within an initialposition. If the position of the field generator coils is altered,however, such as due to bending of the surgical bed, the interactions ofthe surgical tool sensor with the resulting EM field may result inmeasurements that do not correctly reflect the location of the surgicaltool.

In order to avoid inaccurate determinations of surgical tool locations,structures are provided that fully or partially decouple arms used toembed field generator coils from a surgical bed. In this way,disturbances that occur at the surgical bed, such as bending, may bepartially or fully prevented from affecting the EM field generatorsystem.

In a first aspect of the invention, two arms that are adjacent to asurgical bed may be used to embed field generator coils. The arms may besupported using a brace portion. Additionally, the arms may be partiallydecoupled from the surgical bed so as to prevent, or partially prevent,the bending of the surgical bed from affecting the position of the arms.

In a second aspect of the invention, a base connector that connects twohinged arms, that are adjacent to a surgical bed, may rest against abase portion that is even with or below a level of a surgical bed. Inthis way, the base connector of the hinged arms may be in contact withthe base portion independent of the placement or bending of the adjacentsurgical bed. Additionally, the arms may be decoupled from the surgicalbed so as to prevent, or partially prevent, the bending of the surgicalbed from affecting the position of the arms.

In a third aspect of the invention, an intermediate connector thatconnects two hinged arms, that are adjacent to a surgical bed, may restagainst a base portion that is even with or below a level of a surgicalbed. In this way, the intermediate connector of the hinged arms may bein contact with the base portion independent of the placement or bendingof the adjacent surgical bed. Additionally, the arms may be decoupledfrom the surgical bed so as to prevent, or partially prevent, thebending of the surgical bed from affecting the position of the arms.

In another aspect of the invention, a floating electromagnetic fieldgenerator system is provided. The system comprises a surgical bedportion. The system also comprises a brace component disposed within thesurgical bed portion. Additionally, the system comprises a first armthat is attached to the brace component. The first arm may be positionedadjacent to the surgical bed portion. Additionally, the first arm mayhave at least one field generator coil embedded therein. The system alsocomprises a second arm that is attached to the brace component. Thesecond arm may be positioned adjacent to the surgical bed portion.Additionally, the second arm may have at least one field generator coilembedded therein. The second arm may be positioned parallel to the firstarm.

In some embodiments, the brace component is a circular brace component.In some embodiments, the first and the second arm are independent ofmovement the surgical bed portion. In further embodiments, the first andthe second arm are independent of bending of the surgical bed portion.

In some embodiments, the first arm and the second arm are attached tothe brace component using a hinge. In some embodiments, the first armand the second arm are additionally attached using a connectingcomponent. In further embodiments, the connecting component is a baseconnecting component. In additional further embodiments, the connectingcomponent is an intermediate connecting component. In some embodiments,the intermediate connecting component has a width of three inches. Insome embodiments, the intermediate connecting component has a width offive inches. In some embodiments, the intermediate connecting componenthas a width of between three inches and five inches.

In a further aspect of the invention, a floating electromagnetic fieldgenerator system is provided. The system comprises a first surgical bedportion that is connected to, and movable with respect to, a second bedportion. The system also comprises a brace component connected to thefirst surgical bed portion. Additionally, the system comprises a firstarm that is attached to the brace component. The first arm may bepositioned adjacent to the surgical bed portion, and the first armhaving at least one field generator coil connected thereto. The systemalso comprises a second arm that is attached to the brace component. Thesecond arm may be positioned adjacent to the surgical bed portion.Additionally, the second arm may have at least one field generator coilconnected thereto.

In some embodiments, the first and second arm are partially independentof movement of the surgical bed portion. In some embodiments, the firstand second arm are independent of movement of the surgical bed portion.In further embodiments, the first and the second arm are independent ofbending of the surgical bed portion.

In some embodiments, each of the first arm and second arm have aplurality of field generator coils connected thereto. Additionally, insome embodiments, each of the first arm and the second arm has aplurality of field generator coils detachably attached thereto.

Another aspect of the invention provides a floating electromagneticfield generator system is provided. The system comprises a surgical bedportion. The system also comprises a brace component disposed within thesurgical bed portion. Additionally, the system comprises a first hingedarm that is attached to the brace component, the first hinged armpositioned adjacent to the surgical bed portion, and the first hingedarm having at least one field generator coil embedded therein. Thesystem also comprises a second hinged arm that is attached to the bracecomponent, the second hinged arm positioned adjacent to the surgical bedportion, and the second hinged arm having at least one field generatorcoil embedded therein, the second hinged arm positioned parallel to thefirst hinged arm. Further, the system comprises a base connectingcomponent that connects the first hinged arm and the second hinged arm.

In some embodiments, wherein the base connecting component is at a samelevel as the surgical bed. In some embodiments, the base connectingcomponent is below the surgical bed. In some embodiments, the first andthe second arm are independent of movement the surgical bed portion. Insome embodiments, the first and the second arm are independent ofbending of the surgical bed portion.

A further aspect of the invention provides a floating electromagneticfield generator system. The system comprises a surgical bed portion. Thesystem also comprises a brace component disposed within the surgical bedportion. Additionally, the system comprises a first arm that is attachedto the brace component, the first arm positioned adjacent to thesurgical bed portion, and the first arm having at least one fieldgenerator coil embedded therein. The system further comprises a secondarm that is attached to the brace component, the second arm positionedadjacent to the surgical bed portion, and the second arm having at leastone field generator coil embedded therein, wherein the second arm isconnected to the first arm using an intermediate connecting component.

In some embodiments, the intermediate connecting component is at a samelevel as the surgical bed. In some embodiments, the intermediateconnecting component is below the surgical bed. In some embodiments, thefirst arm and the second arm are attached to the brace component using ahinge. In some embodiments, each of the first arm and second arm have aplurality of field generator coils connected thereto. In furtherembodiments, each of the first and second arm have a plurality of fieldgenerator coils detachably attached thereto. Additionally, in someembodiments, each of the first arm and the second arm have a pluralityof field generator coils embedded within.

It shall be understood that different aspects of the invention can beappreciated individually, collectively, or in combination with eachother. Other objects and features of the present invention will becomeapparent by a review of the specification, claims, and appended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described, by way of example, and with referenceto the accompanying drawings, in which:

FIG. 1 illustrates a perspective view of a surgical bed system havingarms for embedding electromagnetic field generator coils, in accordancewith some embodiments;

FIG. 2 illustrates an overhead view of a surgical bed system havingrigid arms for embedding electromagnetic field generator coils, inaccordance with some embodiments;

FIG. 3 illustrates a swivel-top portion of a surgical bed system havingrigidly placed arms for embedding electromagnetic field generator coils,in accordance with some embodiments;

FIG. 4 illustrates an exploded view of a swivel-top portion of asurgical bed system having rigidly placed arms for embeddingelectromagnetic field generator coils, in accordance with someembodiments;

FIG. 5 illustrates a perspective view of underneath a swivel-top portionof a surgical bed system having rigidly placed arms with electromagneticfield generator coils embedded therein, in accordance with someembodiments;

FIG. 6 illustrates a side view of a first position of a swivel-topportion of a surgical bed system having rigidly placed arms forembedding electromagnetic field generator coils, in accordance with someembodiments;

FIG. 7 illustrates a side view of a second position of a swivel-topportion of a surgical bed system having rigidly placed arms forembedding electromagnetic field generator coils, in accordance with someembodiments;

FIG. 8 illustrates a swivel-top portion of a surgical bed system havinghinged arms for embedding electromagnetic field generator coils, inaccordance with some embodiments;

FIG. 9 illustrates an exploded view of a swivel-top portion of asurgical bed system having hinged arms for embedding electromagneticfield generator coils, in accordance with some embodiments;

FIG. 10 illustrates a perspective view of underneath a swivel-topportion of a surgical bed system having hinged arms for embeddingelectromagnetic field generator coils, in accordance with someembodiments;

FIG. 11 illustrates a side view of a first position of a swivel-topportion of a surgical bed system having hinged arms for embeddingelectromagnetic field generator coils, in accordance with someembodiments;

FIG. 12 illustrates a side view of a second position of a swivel-topportion of a surgical bed system having hinged arms for embeddingelectromagnetic field generator coils, in accordance with someembodiments;

FIG. 13 illustrates a perspective view of a surgical bed system havingarms for embedding electromagnetic field generator coils, the armsconnected using a median brace, in accordance with some embodiments;

FIG. 14 illustrates an overhead view of a surgical bed system havingarms connected using a median brace for embedding electromagnetic fieldgenerator coils, in accordance with some embodiments;

FIG. 15 illustrates a swivel-top portion of a surgical bed system havingarms for embedding electromagnetic field generator coils, the armsconnected using a median brace, in accordance with some embodiments;

FIG. 16 illustrates an exploded view of a swivel-top portion of asurgical bed system having arms for embedding electromagnetic fieldgenerator coils, the arms connected using a median brace, in accordancewith some embodiments;

FIG. 17 illustrates a perspective view of underneath a swivel-topportion of a surgical bed system having arms with electromagnetic fieldgenerator coils embedded therein, the arms connected using a medianbrace, in accordance with some embodiments;

FIG. 18 illustrates a side view of a first position of a swivel-topportion of a surgical bed system having arms for embeddingelectromagnetic field generator coils, the arms connected using a medianbrace, in accordance with some embodiments;

FIG. 19 illustrates a side view of a second position of a swivel-topportion of a surgical bed system having arms for embeddingelectromagnetic field generator coils, the arms connected using a medianbrace, in accordance with some embodiments;

FIG. 20 illustrates a schematic of a floating electromagnetic (EM) fieldgenerator system that generates a single field, in accordance with someembodiments;

FIG. 21 illustrates a schematic of a floating electromagnetic (EM) fieldgenerator system that generates multiple fields, in accordance with someembodiments;

FIG. 22 illustrates a block diagram of a closed-loop control EM trackingsurgical system, in accordance with some embodiments;

FIG. 23 illustrates a schematic circuit diagram of an EM trackingsurgical system, in accordance with some embodiments;

FIG. 24 illustrates schematic layouts of field generator coils andworking volumes within an EM tracking surgical system, in accordancewith some embodiments;

FIG. 25 illustrates selective activation of field generator coils andworking volumes as a surgical tool comprising a position sensor moveswithin an EM tracking surgical system, in accordance with someembodiments;

FIG. 26 illustrates selective activation of field generator coils andworking volumes as a surgical tool comprising a plurality of positionsensors moves within an EM tracking surgical system, in accordance withsome embodiments;

FIG. 27 illustrates schematic views of an EM tracking surgical systemhaving reconfigurable bed portions, in accordance with some embodiments;

FIGS. 28A and 28B illustrate sizing of a reconfigurable bed portion ofan EM tracking surgical system based on exemplary dimensions of a humantorso, in accordance with some embodiments;

FIG. 29 illustrates a reconfigurable bed portion of an EM trackingsurgical system, in accordance with some embodiments;

FIG. 30 illustrates dimensions and locations of field generator coils ona reconfigurable bed portion of an EM tracking surgical system, inaccordance with some embodiments;

FIG. 31 illustrates an estimated length of a working volume based on thedimensions of a reconfigurable bed portion of an EM tracking surgicalsystem, in accordance with some embodiments; and

FIG. 32 illustrates an exemplary working volume above a reconfigurablebed portion of an EM tracking surgical system, in accordance with someembodiments.

DETAILED DESCRIPTION

Although certain preferred embodiments and examples are disclosed below,the inventive subject matter extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses, and tomodifications and equivalents thereof. Thus, the scope of the claimsappended hereto is not limited by any of the particular embodimentsdescribed below. For example, in any method or process disclosed herein,the acts or operations of the method or process may be performed in anysuitable sequence and are not necessarily limited to any particulardisclosed sequence. Various operations may be described as multiplediscrete operations in turn, in a manner that may be helpful inunderstanding certain embodiments; however, the order of descriptionshould not be construed to imply that these operations are orderdependent. Additionally, the structures, systems, and/or devicesdescribed herein may be embodied as integrated components or as separatecomponents.

Floating electromagnetic (EM) field generator systems for tracking asurgical tool relative to a surgical bed are provided. The floating EMfield generator system may comprise arms. In particular, the arms thatare next to a surgical bed may have EM field generator coils embeddedtherein. The EM field generator coils may be used to generate an EMfield over at least a portion of the surgical bed. Additionally, thearms may be within a structure that is independent, or at leastpartially independent, from weight-bearing portions of the surgical bed.As such, in examples, floating EM field generator systems may be used todecouple the orientation of field generator coils from bending that mayoccur on a surgical bed.

In examples, an EM field generator may be used as one navigationalcomponent of a surgical tool tracking system that includes visualcomponent and/or a fluoroscopic component. Additionally, systemsprovided that utilize three navigational components may be more accuratein tracking a surgical tool than navigational systems that only use oneor two navigational components.

When using an EM field generator tracking system, a sensor associatedwith a surgical tool may be tracked based on interactions of the sensorwith an electromagnetic field. In particular, a sensor associated with asurgical tool may be tracked when voltage is induced within a sensorcoil that is placed within the electromagnetic field. In examples, thesystem provided may be used for alternating current (AC) EM tracking. Inother examples, the system may be used for direct current (DC) EMtracking.

The electromagnetic field may be calibrated having a predeterminedprecision along a length of a surgical bed in the system. Smallvariations in position can be detected based on the sensor interactionwith the electromagnetic field. The positional variations can have aspatial resolution of less than about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5mm, 4 mm, 3 mm, 2 mm, or 1 mm. In some cases, the spatial resolution maybe greater than about 10 mm. However, once a set of field generatorcoils are embedded, it is beneficial that the field generator coilsremain in the same position, or at least the same position relative tothe other field generator coils. If the field generator coils do notstay in the same position, the calibration of the field generator coilsmay be invalid, and the determined location of the sensor associatedwith the surgical tool may be incorrect.

Accordingly, the system may comprise a plurality of field generatorcoils embedded within arms that are associated with a surgical bed. Thearms having the field generator coils embedded within may be disposedwith respect to the surgical bed. In some examples, the field generatorcoils embedded within the arms may be placed with respect to, butdecoupled from, the surgical bed. In this way, the field generator coilswithin the arms may be protected, or partially protected, fromdisturbances from the surgical bed.

Each field generator coil, or subset of field generator coils, may beconfigured to generate a magnetic field within a control volume. Thecontrol volume may be static. Alternatively, the control volume may becapable of changing dynamically (e.g., time-variable). The system mayfurther comprise a position sensor disposed on a portion of the surgicaltool. The position sensor may be configured to generate a sensor signalin response to the magnetic field when the position sensor is locatedinside the control volume. Additionally, the system may comprise an EMsystem controller configured to selectively activate one or more of thesubsets of field generator coils based on the sensor signal. Further,the system may also comprise a plurality of calibration files thatcorrespond to each individual configuration of activated coils.

In some cases, a physician may need to know the spatial information ofan endoscope relative to the patient's body, using the surgical bed as adatum. The spatial information may include a spatial position and/ororientation of the endoscope in a three-dimensional coordinate system.One or more sensors may be attached to the endoscope to determine thespatial information. The sensors may include electromagnetic (EM)sensors configured to detect the spatial information of the endoscope,as well as movement of the endoscope, within the environment of thesurgical bed. The EM sensors may be used in conjunction with a set offield generator coils that are disposed at or next to the surgical bed.The field generator coils may be configured to produce a calibrated(known) electromagnetic (EM) field over a working volume above and closeto the surgical bed. The working volume may be defined as athree-dimensional space above the surgical bed where a portion of thepatient's body is located. A region of interest on the patient's body(e.g., where a surgical procedure is to be performed) may be disposedwithin the working volume. When the endoscope moves within the workingvolume, the interaction of the EM sensors with the EM field results inelectrical signals (e.g., voltages) being generated. The spatialinformation and/or movement of the endoscope can be determined byanalyzing the electrical signals.

Current state-of-the-art field generator coils may be provided indifferent configurations. For example, in some cases, a flatconfiguration of field generator coils may be placed in a surgical beddirectly under a patient. Alternatively, a box configuration of fieldgenerator coils may be placed externally on a side of the surgical bedor positioned above/over the patient. Optionally, a window configurationof field generator coils may be positioned under the surgical bed orunder the patient. However, each of the above configurations has certaindeficiencies. For example, use of fluoroscopy may be limited in the flatconfiguration because the generator coils constitute radio-opaqueobjects/regions that can obstruct fluoroscopic imaging (e.g., X-rayimaging). The box configuration may interfere with a physician's accessto a patient since the coils are placed externally on the side of thesurgical bed or positioned above/over the patient. In the windowconfiguration, the positioning of coils under the surgical bed mayresult in mechanical and/or electromagnetic interference with otherdevices (e.g., motors for actuating the bed, linear actuator drives,radio-frequency (RF) circuits, etc.) that are also disposed under thesurgical bed. Additionally, the positioning of coils under the patientmay require an overall thickness of the bed to be increased, whichresults in larger form factor and higher manufacturing costs.

Additional drawbacks of one or more of the above coil configurations mayinclude limited range of use. For example, the field generators in theabove configurations typically generate a working volume of about 0.5m×0.5 m×0.5 m, which is often insufficient to encompass a length or awidth of a patient's body. In some instances, the surgical procedure mayinvolve different parts of the patient's body that are spaced outside ofthe typical 0.5 m×0.5 m×0.5 m working volume. In those instances,movement of the coils around the surgical bed may be required, which mayincrease the mechanical complexity of the system and interfere with thephysician's access to the patient.

Accordingly, it would be beneficial to have a floating EM fieldgenerator system and a method of controlling the system that providesimproved navigation, ergonomics, and usability. A floatingelectromagnetic (EM) field generator system for tracking a surgical toolmay be provided in accordance with another aspect of the invention. Thesystem may comprise a plurality of subsets of field generator coilsembedded within arms that are disposed with respect to a surgical bed.Each subset of field generator coils may be configured to generate amagnetic field within a control volume. A central portion of thesurgical bed may be fluoroscopically transparent. The system may alsocomprise a position sensor disposed on a portion of the surgical tool.The position sensor may be configured to generate a sensor signal inresponse to the magnetic field when the position sensor is locatedinside the control volume. The system may further comprise an EM systemcontroller configured to activate one or more of the subsets of fieldgenerator coils.

1. Overview

A floating electromagnetic field generator surgical system is providedin which field generator coils are embedded within arms of a surgicalbed system. In examples, the field generator coils are placed in armsthat are decoupled from movement and/or weight bearing on a bed portionof the surgical bed system. As a patient rests on a bed portion of thesurgical bed, the arms containing the field generator coils may stayrigid. In other examples, the arms may be movable while keeping insteady position relative to each other. Using methods and systemsdiscussed herein, field generator coils within arms of the surgical bedsystem may be relatively stable independent of a weight of a patient ona bed portion of the surgical bed system.

The placement of field generator coils in the disclosed configurationsallows for unobstructed use of fluoroscopic imaging, and allows aphysician to easily access the patient during a surgical procedure.Unlike some conventional systems, the field generator coils in thedisclosed EM tracking surgical systems do not interfere with thephysician's access to the patient. The integration of thick fieldgenerator coils within arms of the surgical bed system may also help tomake beds thicker, which may allow for swivel to occur.

The disclosed configurations of field generator coils as embedded inarms of the surgical bed system also allow a plurality of EM fields tobe selectively activated within different working volumes above thesurgical bed. The selective activation of EM fields within the differentworking volumes can prevent interfering EM fields from being generated,and can reduce EM interference between the field generator coils andother devices. Reduction in EM interference can improve the accuracy andsensitivity with which a surgical tool (e.g., an endoscope having one ormore EM sensors) can be tracked within the different working volumesabove the surgical bed. Additionally, the disclosed configurations offield generator coils can extend the range of use of the system by aphysician, since the working volumes can be configured to extend along alength of the surgical bed or in other configurations, depending on therequirements and complexity of the surgical procedure.

In additional examples, tracking of a surgical tool can be facilitatedby activating different subsets of field generator coils. In examples,different subsets of field generator coils may be activated depending onthe location of the surgical procedure relative to the surgical bed.Additionally, in examples, coils outside of the active subset(s) offield generator coils are inactive, thereby preventing interfering EMfields from being generated. In some examples, the working volumes aboveadjacent subsets of field generator coils may overlap so as to form acontinuous global working volume along the length of the surgical bed.In addition, the calibration files needs to be swapped for eachconfiguration.

For purposes of comparing various embodiments, certain aspects andadvantages of these embodiments are described. Not necessarily all suchaspects or advantages are achieved by any particular embodiment. Thus,for example, various embodiments may be carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other aspects or advantages as mayalso be taught or suggested herein.

2. Views of Floating EM Field Generator System

FIG. 1 illustrates a perspective view of a surgical bed system havingarms for embedding electromagnetic field generators, in accordance withsome embodiments. In particular, FIG. 1 illustrates a surgical bed 100positioned on a base component 105. Surgical bed 100 may have a firstportion 110 and a second portion 120, the first portion 110 having arms115 that may be used to embed field generator coils (not shown). Inexamples, arms 115 may be connected and structurally supported using abrace component.

The brace component may help to support the arms so as to preventbending and/or twisting of the arms when disturbances may occur furtherdown the surgical bed. In examples, disturbances may occur in thesurgical bed due to bending of the surgical bed due to the weight of apatient, hanging equipment, physician interaction, etc. In examples,bending and/or twisting of the arms may modify the EM field that isgenerated using field generator coils, thereby making the tracking of asurgical tool within the EM field less accurate. As such, decoupling thebending moment and/or lessening disruption of the surgical bed from thefield generator coils embedded in arms of the surgical bed may improveaccuracy of a tracking system that utilizes the EM field generated bythe floating EM field generator system.

FIG. 2 illustrates an overhead view of a surgical bed system of FIG. 1having rigid arms for embedding electromagnetic field generators, inaccordance with some embodiments. In particular, surgical bed system 100as shown in FIG. 2 illustrates another view of first portion 110, secondportion 120, and arms 115 as presented in FIG. 1. As seen in FIG. 2,arms 115 may be placed in rows that are parallel with respect to oneanother. There may be two sets of calibration, the device calibrationand registration. In examples, registration occurs when arms 115 may beat different levels with respect to one another and relative to thepatient. At times when registration is off, the device can still performas expected. In examples, registration may be done with arms 115 atvarious positions relative to the patient. However, if the coils aredisplaced from their relative positions with respect to one another atthe time of device calibration, the device may not perform as expected.

FIG. 3 illustrates a swivel-top portion 300 of a surgical bed systemhaving rigidly placed arms for embedding electromagnetic field generatorcoils, in accordance with some embodiments. The swivel top provides theability to swivel the torso portion of the platform away from thelongitudinal axis, allowing for positioning the patient's groin over theside of the platform so that open access is provided for the surgicalarms. In particular, FIG. 3 illustrates a bed component 310, a brace(not shown), arms 330, bed rails 340, and securing components 350. Asseen in FIG. 3, the position of arms 330 relative to one another ismaintained based on rigidly connecting arms 330 to a base structure,such as a brace. The brace may be made from a stainless steel bearingblock embedded into structural foam and firmly rooted in place withresin, and/or may be completely encapsulated in Carbon Fiber. In someexamples, this is the stiffest point of the bed that can be approximatedto have zero deflection.

FIG. 4 illustrates an exploded view of a swivel-top portion of asurgical bed system having rigidly placed arms for embeddingelectromagnetic field generator coils, in accordance with someembodiments. In particular, FIG. 4 illustrates an exploded view of aswivel-top portion 300 as seen in FIG. 3. As such, FIG. 4 illustrates abed component 310, a brace 320, arms 330, bed rails 340, and securingcomponents 350. Additionally, FIG. 4 illustrates spacers 355.

As seen in FIG. 4, arms 330 may individually be attached to brace 320.In examples, brace 320 and arms 330 may be formed from a singlecomponent. In additional examples, arms 330 may be used to embed one ormore field generator coils (not shown). Further, arms 330 may bedecoupled from bed 310 so as to allow bed 310 to bend without placing adirect pressure on arms 330. In examples, bed 310 may bend due to theweight of a patient. The weight of the patient may also affect brace320. In some examples, the structure of brace 320 may be reinforced bythe brace material and/or the circular component of the brace 320 so asto prevent bending within arms 330 attached to brace 320. In furtherexamples, arms 330 may be moved in a direction associated with thesurgical bed in response to the weight of a patient. However, the rigidmaterial of arms 330 and/or brace 320 may be used to keep the arms 330rigid even as they are displaced through space. In this way, arms 330may move downwards, but may have a rigid structure with respect to oneanother.

FIG. 5 illustrates a perspective view of underneath a swivel-top portionof a surgical bed system having rigidly placed arms with electromagneticfield generator coils embedded therein, in accordance with someembodiments. In particular, FIG. 5 illustrates an exploded view of aswivel-top portion 300 as seen in FIG. 3. As such, FIG. 5 illustrates abed component 310, a brace 320, arms 330, bed rails 340, securingcomponents 350, and spacers 355. Additionally, FIG. 5 illustrates fieldgenerator coils 360. As seen in FIG. 5, field generator coils 360 may beplaced at an equal distance apart from one another. In other examples,field generator coils 360 may be placed at unequal distances from oneanother. In some examples, the distance between field generator coils360 may be due to design of the arms 330. As seen in FIG. 5, fieldgenerator coils 360 may be embedded in arms 330 and, as such, may beplaced with respect to bed component 310 based on a placement of arms330 with respect to bed component 310.

FIG. 6 illustrates a side view of a first position of a swivel-topportion 300 of a surgical bed system having rigidly placed arms forembedding electromagnetic field generator coils, in accordance with someembodiments. Additionally, FIG. 7 illustrates a side view of a secondposition of a swivel-top portion of a surgical bed system having rigidlyplaced arms for embedding electromagnetic field generator coils, inaccordance with some embodiments. As seen in FIGS. 6 and 7, as a bedcomponent and bed rails 340 move downwards from a first position to asecond position, arms 330 may stay stable. In particular, arms 330 maystay rigid independent of the movement and/or bending of bed componentbased on the bracing of arms 330 using brace 320.

FIG. 8 illustrates a swivel-top portion 800 of a surgical bed systemhaving hinged arms for embedding electromagnetic field generator coils,in accordance with some embodiments. In particular, FIG. 8 illustrates abed component 810, a brace (not shown), arms 830, bed rails 840, andsecuring components 850. As seen in FIG. 8, the position of arms 830relative to one another is maintained based on connecting arms 830 to abase structure 820, as well as connecting arms 830 using a baseconnecting component 825. By using base connecting component 825, thearms' hinge-like movement of arms 830 may be equal such that the arms830 maintain their position with respect to each other. In examples,where arms maintain a stable position with respect to each other, thecharacteristics of a field generated using field generator coils withinthe arms 830 may also be stabilized.

FIG. 9 illustrates an exploded view of a swivel-top portion of asurgical bed system having hinged arms for embedding electromagneticfield generator coils, in accordance with some embodiments. Inparticular, FIG. 9 illustrates an exploded view of a swivel-top portion800 as seen in FIG. 8. As such, FIG. 9 illustrates a bed component 810,a brace 820, a base connecting component 825, arms 830, bed rails 840,and securing components 850. Additionally, FIG. 9 illustrates spacers855.

FIG. 10 illustrates a perspective view of underneath a swivel-topportion 800 of a surgical bed system having hinged arms for embeddingelectromagnetic field generator coils, in accordance with someembodiments. As such, FIG. 10 illustrates a bed component 810, a brace820, a base connecting component 825, arms 830, bed rails 840, securingcomponents 850, and spacers 855. Additionally, FIG. 10 illustrates fieldgenerator coils 860 (e.g., within arms 830). As seen in FIG. 10, fieldgenerator coils may be placed at an equal distance apart from oneanother. In other examples, field generator coils may be placed atunequal distances from one another. In some examples, the distancebetween field generator coils, such as field generator coils 860, may bedue to design of the arms, such as arms 830. In some examples, thedistance between the field generator coils may be based on a surgicalprocedure to be performed. As seen in FIG. 10, field generator coils maybe embedded in arms 830 and, as such, may be placed with respect to bedcomponent 810 based on a placement of arms 830 with respect to bedcomponent 810.

FIG. 11 illustrates a side view of a first position of a swivel-topportion 800 of a surgical bed system having hinged arms for embeddingelectromagnetic field generator coils, in accordance with someembodiments. Additionally, FIG. 12 illustrates a side view of a secondposition of a swivel-top portion of a surgical bed system having hingedarms for embedding electromagnetic field generator coils, in accordancewith some embodiments. As seen in FIGS. 11 and 12, as bed component 810moves downwards from a first position to a second position, arms 830 maystay stable at a position that is lower or level with bed component 810.Either way, arms 830 may stay in a same position independent of movementof bed portion 810. In examples, arms 830 and base connecting component825 may rest against a further support, such as a base, to furthersupport arms 830 and base connecting component 825.

FIG. 13 illustrates a perspective view of a surgical bed system havingarms for embedding electromagnetic field generator coils, the armsconnected using a median brace, in accordance with some embodiments. Inparticular, FIG. 13 illustrates a surgical bed 1300 positioned on a basecomponent 1305. Surgical bed 1300 may have a first portion 1310 and asecond portion 1320, the first portion 1310 having arms 1315 that may beused to embed field generator coils (not shown). In examples, arms 1315may be connected and structurally supported using an intermediate bracecomponent 1330.

FIG. 14 illustrates an overhead view of a surgical bed system havingarms connected using a median brace for embedding electromagnetic fieldgenerator coils, in accordance with some embodiments. In particular,surgical bed 1300 as shown in FIG. 14 illustrates another view of firstportion 1310, second portion 1320, and arms 1315 as presented in FIG.13. As seen in FIG. 14, arms 1315 may be placed in rows that areparallel with respect to one another. Additionally, arms 1315 areattached using an intermediate brace component 1330. The structuralsupport of arms 1315 using an intermediate brace component 1330 may beused to prevent bending of arms 1315 when a patient is on bed 1300.

FIG. 15 illustrates a swivel-top portion 1500 of a surgical bed systemhaving arms for embedding electromagnetic field generator coils, thearms connected using a median brace, in accordance with someembodiments. In particular, FIG. 15 illustrates a bed component 1510,arms 1530, intermediate brace component 1535, bed rails 1540, andsecuring components 1550. As seen in FIG. 15, the position of arms 1530relative to one another is maintained based on rigidly connecting arms1530 to intermediate brace component 1535. In examples, intermediatebrace component 1535 may have a band that is three inches wide. In someexamples, the band of intermediate brace component 1535 is less thanthree inches wide, and in some examples, the band of intermediate bracecomponent 1535 is more than three inches wide. In examples, the band ofintermediate brace component 1535 may be less than an inch; may be aninch; may be 1.5 inches; may be 2 inches; may be 2.5 inches; may be 3inches; may be 3.5 inches; may be 4 inches; may be 4.5 inches; may be 5inches; or may be more than 5 inches.

FIG. 16 illustrates an exploded view of a swivel-top portion of asurgical bed system having arms for embedding electromagnetic fieldgenerator coils, the arms connected using a median brace, in accordancewith some embodiments. In particular, FIG. 16 illustrates an explodedview of a swivel-top portion 1500 as seen in FIG. 15. As such, FIG. 16illustrates a bed component 1510, circular brace component 1520, arms1530, intermediate brace component 1535, bed rails 1540, and securingcomponents 1550. Additionally, FIG. 16 illustrates spacers 1555.

As seen in FIG. 16, arms 1530 may be joined through their attachment tointermediate brace component 1535. Additionally, arms 1530 may be joinedto another, circular base component 1520 within bed component 1510. Inexamples, circular brace component 1520, arms 1530, and intermediatebrace component 1535 may be formed from a single component. Inadditional examples, arms 1530 may be used to embed one or more fieldgenerator coils (not shown). Further, arms 1530 may be decoupled frombed component 1510 so as to allow bed component 1510 to bend withoutplacing a direct pressure on arms 1530. In examples, bed component 1510may bend due to the weight of a patient. The weight of the patient mayalso affect circular brace component 1520 and/or intermediate bracecomponent 1535, but the structure of circular brace component 1520and/or intermediate brace component 1535 may be reinforced by the bracematerial and/or the shape of the brace component so as to preventbending within arms 1530 attached to brace components 1520 and/or 1535.In further examples, arms 1530 may be moved in a direction associatedwith the surgical bed in response to the weight of a patient. However,the rigid material of circular brace component 1520, arms 1530, and/orintermediate brace component 1535 may be used to keep the arms 1530rigid even as they are displaced through space. In this way, arms 1530may move downwards, but may have a rigid structure with respect to oneanother.

FIG. 17 illustrates a perspective view of underneath a swivel-topportion of a surgical bed system having arms with electromagnetic fieldgenerator coils embedded therein, the arms connected using a medianbrace, in accordance with some embodiments. As such, FIG. 17 illustratesa bed component 1510, a brace 1520, arms 1530, an intermediate bracecomponent 1535, bed rails 1540, securing components 1550, and spacers1555. Additionally, FIG. 17 illustrates field generator coils 1560. Asseen in FIG. 17, field generator coils 1560 may be placed at an equaldistance apart from one another. In other examples, field generatorcoils 1560 may be placed at unequal distances from one another. In someexamples, the distance between field generator coils 1560 may be due todesign of the arms 1530. In some examples, the distance between thefield generator coils 1560 may be based on a surgical procedure to beperformed. As seen in FIG. 17, field generator coils 1560 may beembedded in arms 1530 and, as such, may be placed with respect to bedcomponent 1510 based on a placement of arms 1530 with respect to bedcomponent 1510.

FIG. 18 illustrates a side view of a first position of a swivel-topportion of a surgical bed system having arms for embeddingelectromagnetic field generator coils, the arms connected using a medianbrace, in accordance with some embodiments. FIG. 19 illustrates a sideview of a second position of a swivel-top portion of a surgical bedsystem having arms for embedding electromagnetic field generator coils,the arms connected using a median brace, in accordance with someembodiments. As seen in FIGS. 18 and 19, as bed component 1510 movesdownwards from a first position to a second position, arms 1530 may staystable. In particular, arms 1530 may stay rigid independent of themovement and/or bending of surgical bed 1510 based on the bracing ofarms 1530 using circular brace component (not shown) and intermediatebrace component (not shown). Additionally, FIGS. 18 and 19 illustratesecuring components 1550.

System Components

FIG. 20 illustrates a schematic of a floating EM field generator system2000 that generates a single field 2012, in accordance with someembodiments. As shown in FIG. 20, the floating EM field generator system2000 may also comprise a surgical bed 2002 that rests on a base 2001, aplurality of field generator coils 2003, an EM system controller 2008, aswitch module 2010, and a position sensor 2016.

The surgical bed 2002 may be configured to support a patient. Aphysician may perform a surgical procedure on the patient while thepatient is placed on the surgical bed 2002. In some embodiments, thesurgical bed 2002 may comprise multiple sections that are movablerelative to one another. In those embodiments, the patient's body can bemoved into different positions by moving different sections of thesurgical bed 2002 relative to one another. Alternatively, the surgicalbed 2002 may be formed monolithically as a single rigid structure.

The plurality of field generator coils 2003 may be embedded orintegrated within arms 2014 associated with the surgical bed 2002. Forexample, as shown in FIG. 20, the plurality of field generator coils2003 may be embedded within arms (not shown) associated with thesurgical bed 2002 in two rows. The rows may extend parallel to eachother along the edge of the surgical bed 2002. As previously mentioned,the field generator coils 2003 constitute radio-opaque objects/regions.Accordingly, the placement of the field generator coils 2003 within armsnext to surgical bed 2002 can allow unobstructed use of fluoroscopy toimage the patient's body during a surgical procedure.

In some examples, a plurality of working volumes 2112 may be generatedusing subsets of field generator coils 2104. This is shown in FIG. 21,which illustrates a schematic of a floating EM field generator systemthat generates multiple fields, in accordance with some embodiments. Asseen in FIG. 21, the plurality of working volumes 2112 may include afirst working volume 2102-1, a second working volume 2102-2, and a thirdworking volume 2102-3. Each working volume 2112 may be associated with asubset of field generator coils, and may be disposed directly above therespective subset of field generator coils. For example, the firstworking volume 2102-1 may be disposed directly above the first subset offield generator coils 2104-1, the second working volume 2102-2 may bedisposed directly above the second subset of field generator coils2104-2, and the third working volume 2102-3 may be disposed directlyabove the third subset of field generator coils 2104-3.

The plurality of field generator coils 2003 may include, and can begrouped into, subsets as field generator coils 2104. For example, asshown in FIG. 21, the field generator coils 2003 may include a firstsubset of field generator coils 2104-1, a second subset of fieldgenerator coils 2104-2, and a third subset of field generator coils2104-3. Although three subsets are illustrated in FIG. 21, it should benoted that the invention is not limited thereto, and that any number ofsubsets of field generator coils may be contemplated. In examples, 2, 3,4, 5, 6, 7, 8, 9, 10, or more than 10 subsets of field generator coilsmay be used.

Each subset of field generator coils 2104 may comprise a number of fieldgenerator coils. In FIG. 21, each subset of field generator coils2104-1, 2104-2, and 2104-3 may comprise six, ten, or six field generatorcoils, respectively. However, each subset of field generator coils neednot be limited to six field generator coils. In some embodiments, asubset of field generator coils may comprise more than six fieldgenerator coils. For example, a subset of field generator coils maycomprise 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30,35, 40, or more than 40 field generator coils. In other embodiments, asubset of field generator coils may comprise six or less generatorcoils. For examples, a subset of field generator coils may comprise 1,2, 3, 4, 5, or 6 field generator coils. In some embodiments, differentsubsets of field generator coils may comprise different numbers of fieldgenerator coils. Any number of field generator coils within each subset,and between different subsets, may be contemplated.

The field generator coils within each subset may be fixed in placerelative to one another. For example, the field generator coils may bespaced apart by a predetermined distance and/or at a predefined pitchalong the edges of the surgical bed 2002. Additionally, the fieldgenerator coils may be nominally fixed relative to the surgical bed 2002in a global coordinate system. Any portion of the surgical bed 2002 mayserve as an origin of the global coordinate system. In some embodiments,a datum point that lies substantially above a center portion of thesurgical bed 2002 may serve as the origin of the global coordinatesystem. In those embodiments, the positions of the field generator coilsmay be defined relative to the datum point.

The EM system controller 2008 may be configured to provide electricalcurrent pulses to the field generator coils 2003 to generate an EM fieldover the respective working volume 2112 above each subset of fieldgenerator coils 2104. The EM system controller 2008 can selectivelyactivate (power on) different subsets of field generator coils 2104 togenerate EM fields in different working volumes 2112 by controlling oneor more switches in the switch module 2010. Electrical current pulsesmay be provided from the EM system controller 2008 to the differentsubsets of field generator coils 2104 via one or more switches in theswitch module 2010.

The switches may include electronic switches such as power MOSFETs,solid state relays, power transistors, and/or insulated gate bipolartransistors (IGBTs). Different types of electronic switches may beprovided for controlling current to a subset of field generator coils.An electronic switch may utilize solid state electronics to controlcurrent flow. In some instances, an electronic switch may have no movingparts and/or may not utilize an electro-mechanical device (e.g.,traditional relays or switches with moving parts). In some instances,electrons or other charge carriers of the electronic switch may beconfined to a solid state device. The electronic switch may optionallyhave a binary state (e.g., switched-on or switched-off). The electronicswitches may be used to control current flow to the subsets of fieldgenerator coils. The operation of switches to selectively activate oneor more subsets of field generator coils is described with reference toFIG. 23, below.

The EM system controller 2008 can control the switches to activate: (1)the first subset of field generator coils 2104-1 to generate an EM fieldin the first working volume 2102-1, (2) the second subset of fieldgenerator coils 2104-2 to generate an EM field in the second workingvolume 2102-2, and/or (3) the third subset of field generator coils2104-3 to generate an EM field in the third working volume 2102-3. Inexamples, the subsets of field generator coils may be activatedsimultaneously. In some examples, the subsets of field generator coilsmay be activated sequentially. For example, in some embodiments, the EMsystem controller 2008 can simultaneously activate all three subsets offield generator coils 2104 to create three separate EM fields in therespective working volumes 2112. Alternatively, the EM system controller2008 can sequentially activate the first, second, and third subsets offield generator coils 2104-1, 2104-2, and 2104-3 to sequentiallygenerate EM fields in the first, second, and third working volumes2102-1, 2102-2, and 2102-3.

The EM system controller 2008 can be configured to activate one or moresubsets of field generator coils without activating one or more othersubsets of field generator coils. For example, in some embodiments, theEM system controller 2008 can activate only the first subset of fieldgenerator coils 2104-1 without activating the second and third subsetsof field generator coils 2104-2 and 2104-3. Similarly, the EM systemcontroller 2008 can activate only the second subset of field generatorcoils 2104-2 without activating the first and third subsets of fieldgenerator coils 2104-1 and 2104-3. Likewise, the EM system controller2008 can activate only the third subset of field generator coils 2104-3without activating the first and second subsets of field generator coils2104-1 and 2104-2. In some cases, the EM system controller 2008 canactivate the first and second subsets of field generator coils 2104-1and 2104-2 without activating the third subset of field generator coils2104-3. In other cases, the EM system controller 2008 can activate thesecond and third subsets of field generator coils 2104-2 and 2104-3without activating the first subset of field generator coils 2104-1.Optionally, the EM system controller 108 can activate the first andthird subsets of field generator coils 2104-1 and 2104-3 withoutactivating the second subset of field generator coils 2104-2. Additionalcombinations (of the activation) of different subsets of field generatorcoils may be contemplated.

As previously described, the EM system controller 2008 can sequentiallyactivate the first, second, and third subsets of field generator coils2104-1, 2104-2, and 2104-3. In some embodiments, all three subsets offield generator coils may continue to be powered on after they have beensequentially activated. For example, the first subset of field generatorcoils 2104-1 may continue to be powered on after the second subset offield generator coils 2104-2 has been activated. The first and secondsubsets of field generator coils 2104-1 and 2104-2 may continue to bepowered on after the third subset of field generator coils 2104-3 hasbeen activated. Alternatively, in some embodiments, the first subset offield generator coils 2104-1 may be powered off after the second subsetof field generator coils 2104-2 has been activated, and the secondsubset of field generator coils 2104-2 may be powered off after thethird subset of field generator coils 2104-3 has been activated.

In some embodiments, the EM system controller 2008 may be located on thesurgical bed 2002, for example on a base configured to support thesurgical bed 2002. In some embodiments, the EM system controller 2008may be located remotely from the surgical bed 2002. For example, the EMsystem controller 2008 may be disposed in a remote server that is incommunication with the subsets of field generator coils 2004 and theswitch module 2010. The EM system controller 2008 may be software and/orhardware components included with the server. The server can have one ormore processors and at least one memory for storing programinstructions. The processor(s) can be a single or multiplemicroprocessors, field programmable gate arrays (FPGAs), or digitalsignal processors (DSPs) capable of executing particular sets ofinstructions. Computer-readable instructions can be stored on a tangiblenon-transitory computer-readable medium, such as a flexible disk, a harddisk, a CD-ROM (compact disk-read only memory), and MO(magneto-optical), a DVD-ROM (digital versatile disk-read only memory),a DVD RAM (digital versatile disk-random access memory), or asemiconductor memory. Alternatively, the program instructions can beimplemented in hardware components or combinations of hardware andsoftware such as, for example, ASICs, special purpose computers, orgeneral purpose computers.

The EM system controller 2008 may also be provided at any other type ofexternal device (e.g., a remote controller for controlling the surgicalbed 2002 and/or a surgical tool, any movable object or non-movableobject, etc.). In some instances, the EM system controller 2008 may bedistributed on a cloud computing infrastructure. The EM systemcontroller 2008 may reside in different locations where the EM systemcontroller 2008 is capable of controlling the switch module 2010 andselectively activating one or more subsets of field generator coils 2004based on the spatial information of the position sensor 2016.

The position sensor 2016 may be disposed in or on a portion of asurgical tool. For example, in some embodiments, the position sensor2016 may be disposed at a distal end of the surgical tool. Examples ofsurgical tools may include endoscopes, catheters, ureteroscopes,forceps, different types of scopes, or other similar devices or surgicalaccessories.

A position sensor, such as position sensor 2016, may be configured togenerate an electrical signal (voltage or current signal) in response toEM fields generated field generator coils. Position sensor 2016 may bean EM sensor. As position sensor 2016 moves within a control volume2012, the interaction of the position sensor 2016 with the EM fieldwithin the control volume 2012 may cause electrical signals to begenerated. The electrical signals may vary as the position sensor 2016moves between different locations within a control volume 2012.Additionally, electrical signals may vary as the position sensor 2016moves between different control volumes. The EM system controller 2008may be configured to receive electrical signals from the position sensor2016. Additionally, the EM system controller 2008 may analyze thesignals to compute a local position of the sensor 2016. The localposition of the sensor 2016 may be computed relative to a localcoordinate system. The local coordinate system may be defined at anactive set of field generator coils corresponding to the control volume2012 in which the position sensor 2016 is located.

The EM system controller 2008 may be further configured to compute aglobal position of the sensor 2016 relative to a global coordinatesystem. The global coordinate system may be defined at the surgical bed2002 (e.g., above a center portion of the surgical bed 2002). The globalposition of the sensor 2016 may be computed based on: (1) the localposition of the sensor 2016 within the control volume 2012 above anactive set of field generator coils, and (2) the position of the activeset of field generator coils relative to the surgical bed 2002. Theglobal position of the sensor 2016 may be used to determine a positionof a surgical tool relative to a patient on the surgical bed 2002.

The EM system controller 2008 may be configured to control the switchmodule 2010 based on one or more inputs. The control of the switchmodule 2010, and the selective activation of one or more field generatorcoils, may be manual and/or automatic.

In some embodiments, the EM system controller 2008 may control theswitch module 2010 based on a user input corresponding to a selection ofa region (or working volume 2112) of the surgical bed 2002 wheretracking of a surgical tool is desired. For example, a physician mayplan to perform a surgical procedure on a patient in a region within thefirst working volume 2112-1. Accordingly, the physician or thephysician's assistant may provide an input to the EM system controller2008 to activate the first subset of field generator coils 2104-1, sothat movement of the surgical tool can be tracked within the firstcontrol volume via the position sensor 2016.

In some embodiments, the EM system controller 2008 may control theswitch module 2010 based on an initialization input. The initializationinput may cause the EM system controller 2008 to control the switchmodule 2010 to sequentially activate (cycle through) the subsets offield generator coils 2104, so as to determine: (1) whether the positionsensor 2016 is present in any of the control volumes 2112, (2) in whichcontrol volume 2112 the position sensor 2016 is located if the positionsensor 2016 is detected, and (3) the position of the sensor 2016 withinthe detected control volume 2112. Accordingly, the EM system controller2008 can control the switch module 2010 to activate the subset of fieldgenerator coils 2104 corresponding to the control volume 2112 in whichthe position sensor 2016 is located, without activating the othersubsets of field generator coils.

During the sequential activation (cycling) of the subsets of fieldgenerator coils 2104, the local position of the sensor 2016 relative tothe local coordinate system of the working volume 2112 (where the sensor2016 is located) may be determined. The local position of the sensor2016 may be determined based on a distance between the sensor 2016 and areference point in the local coordinate system. The reference point maylie anywhere in the local coordinate system. For example, in someembodiments, the reference point may be at an origin of the localcoordinate system. One or more subsets of field generator coils 2104 maybe activated based on the distance between the sensor 2016 and thereference point.

For example, when the reference point is an origin of a local coordinatesystem that is defined at a center of a control volume 2112, and theposition sensor 2016 is located at or near the reference point, only thesubset of field generator coils corresponding to that control volume2112 may be activated. Conversely, when the position sensor 2016 islocated far away from the reference point such that the sensor 2016 isproximate to another control volume 2112, adjacent subsets of fieldgenerator coils 2104 corresponding to both control volumes 2112 may beactivated. It should be noted that the local coordinate system need notbe defined at the center of a control volume 2112. In some otherinstances, the local coordinate system may be defined near an edge orcorner of a control volume 2112. Any placement of the reference pointand/or the local coordinate system within a control volume 2112 may becontemplated.

In some embodiments, the local position of the sensor 2016 may bedetermined based on distances between the sensor 2016 and a plurality ofreference points in different local coordinate systems. The differentlocal coordinate systems may lie in different control volumes 2012. TheEM system controller 2008 may be configured to determine a minimumdistance from those distances, and activate a subset of field generatorcoils 2104 corresponding to the control volume 2012 based on the minimumdistance.

During a surgical procedure, the EM system controller 2008 may beconfigured to track the position and/or movement of the sensor 2016within a control volume 2112 corresponding to an active subset of fieldgenerator coils 2104. As the position sensor 2016 moves between adjacentcontrol volumes 2112, different subsets of field generator coils 2104may be selectively activated to ensure that the sensor 2016 iscontinuously tracked, while at the same time reducing EM fieldinterference effects.

3. Closed-Loop Positional and Speed Feedback

FIG. 22 illustrates a block diagram of a closed-loop control EM trackingsurgical system, in accordance with some embodiments. As shown in FIG.22, a closed-loop control EM tracking surgical system 2200 may comprisean EM system controller 2208, a plurality of subsets of field generatorcoils 1 through n, represented as 2204, and a position sensor 2216operably connected via a feedback loop 2207. Any number (n) of subsetsof field generator coils 2204 may be contemplated, and may depend inpart on the strength of each subset of field generator coils 2204 and/ora size (e.g., length and width) of a surgical bed (e.g., surgical bed102 of FIG. 1).

In FIG. 22, a surgical tool may be automatically controlled using one ormore robotic arms that are in operable communication with the EM systemcontroller 2208. The EM system controller 2208 may be configured totrack and control the position and/or movement of the surgical tool, andselectively activate one or more subsets of field generator coils 2204,based on positional and speed feedback of the position sensor 2216 asthe sensor 2216 moves between different control volumes (e.g., controlvolumes 2112 of FIG. 21).

As shown in FIG. 22, an input may be initially provided to the EMtracking surgical system 2200. The input may comprise a desired positionand/or speed of a surgical tool. The position and/or speed of thesurgical tool may be controlled using the one or more robotic arms. TheEM system controller 2208 may be configured to activate one or moresubsets of field generator coils 2204, and to determine a control volume(e.g., control volume 2012 of FIG. 20) in which the position sensor 2216is located. Once the control volume has been determined, the subset offield generator coils 2204 corresponding to that control volume may beactivated while the other subsets of field generator coils 2204 may bepowered off. As previously described, the selective activation ofdifferent subsets of field generator coils 2204 can reduce EM fieldinterference effects. The position and/or movement of the sensor 2216may be determined based on the interaction of the sensor 2216 with theEM field within the control volume. The actual position and/or speed ofthe surgical tool may be determined based on the position and/ormovement of the sensor 2216, and may be compared against the input todetermine an amount of deviation Δ (if any) from the desired positionand/or speed of the surgical tool. The EM system controller 2208 may beconfigured to adjust the actual position and/or speed of the surgicaltool (via the one or more robotic arms) based on the amount ofdeviation.

4. Switching Circuit

FIG. 23 illustrates a schematic circuit diagram of an EM trackingsurgical system, in accordance with some embodiments. As shown in FIG.23, an EM tracking surgical system 2300 may comprise a plurality ofsubsets of field generator coils 2304-1, 2304-2, and 2304-3 electricallyconnected to a power supply 2318. An EM system controller 2308 may be inoperable communication with a plurality of switches K1, K2, and K3 and aposition sensor 2316. The plurality of switches K1, K2, and K3 may belocated in a switch module (e.g., switch module 2010 of FIG. 20). The EMsystem controller 2308 may be configured to selectively activate one ormore subsets of field generator coils 2304, either simultaneously,sequentially, or in a round-robin configuration, based on a positionand/or movement of the position sensor 2316 within and/or betweenadjacent control volumes (e.g., control volumes 2112 of FIG. 21).

The EM system controller 2308 may be configured to control one or moreswitches to selectively activate one or more subsets of field generatorcoils 2304. For example, the EM system controller 2308 may selectivelyactivate the first subset of field generator coils 2304-1 by closing theswitch K1. Similarly, the EM system controller 2308 may selectivelyactivate the second subset of field generator coils 2304-2 by closingthe switch K2. Likewise, the EM system controller 2308 may selectivelyactivate the third subset of field generator coils 104-3 by closing theswitch K3. In some embodiments, the EM system controller 2308 maysimultaneously activate two or more subsets of field generator coils2304. For example, the EM system controller 2308 may simultaneouslyactivate the first and second subsets of field generator coils 2304-1and 2304-2 by closing the switches K1 and K2. Similarly, the EM systemcontroller 2308 may simultaneously activate the first and third subsetsof field generator coils 2304-1 and 2304-3 by closing the switches K1and K3. Likewise, the EM system controller 2308 may simultaneouslyactivate the second and third subsets of field generator coils 2304-2and 2304-3 by closing the switches K2 and K3. Optionally, the EM systemcontroller 2308 may simultaneously activate the first, second, and thirdsubsets of field generator coils 2304-1, 2304-2, and/or 2304-3 bysimultaneously closing the switches K1, K2, and/or K3, respectively. Insome embodiments, the EM system controller 2308 may sequentially closethe switches K1, K2, and/or K3. In some other embodiments, the EM systemcontroller 2308 may close the switches K1, K2, and/or K3 in alternatingmanner. In some embodiments, the EM system controller 2308 may close theswitches K1, K2, and/or K3 at a same frequency or at differentfrequencies. In some embodiments, the EM system controller 2308 mayclose/open the switches K1, K2, and/or K3 for different lengths of time,so as to activate or power off the subsets of field generator coils 2304for different lengths of time.

5. Layout of Field Generator Coils and Working Volumes

FIG. 24 illustrates schematic layouts of field generator coils andworking volumes within an EM tracking surgical system, in accordancewith some embodiments. Part A of FIG. 24 illustrates a schematic sideview of a portion of an EM tracking surgical system 2400, and Part B ofFIG. 24 illustrates a schematic top view of the portion of the system2400.

As shown in FIG. 24, a first subset of field generator coils 2404-1 anda second subset of field generator coils 2404-2 may be embedded along alength portion of a surgical bed 2402. A first working volume 2412-1 maybe defined above the first subset of field generator coils 2404-1, and asecond working volume 2412-2 may be defined above the second subset offield generator coils 2404-2. The dimensions of the first working volume2412-1 may be given by a length L1, a width W, and a height H. Thedimensions of the second working volume 2412-2 may be given by a lengthL2, a width W, and a height H. In some embodiments, the lengths L1 andL2 may be substantially the same. In other embodiments, the lengths L1and L2 may be different. For example, in some instances, the length L1may be less than the length L2. In other instances, the length L1 may begreater than the length L2. In some alternative embodiments (not shown),the widths of the first and second working volumes 2412 may bedifferent. Optionally, the heights of the first and second workingvolumes 2412 may be different.

Each working volume 2412 may comprise a sub-volume threshold locatedwithin each working volume. The sub-volume threshold is located at aboundary between overlapping working volumes. The sub-volume thresholdmay correspond to a transition zone as the sensor moves betweenoverlapping working volumes. For example, the first working volume2412-1 may comprise a first sub-volume threshold 2413-1, and the secondworking volume 2412-2 may comprise a second sub-volume threshold 2413-2.The first sub-volume threshold 2413-1 may have a length L1′, and thesecond sub-volume threshold 2413-2 may have a length L2′. In someembodiments, the lengths L1′ and L2′ may be substantially the same. Inother embodiments, the lengths L1′ and L2′ may be different. The widthsof the first and second sub-volume thresholds may be the same, and theheights of the first and second sub-volume thresholds may be the same.In some alternative embodiments (not shown), the widths of the first andsecond sub-volume thresholds may be different. Optionally, the heightsof the first and second sub-volume thresholds may be different.

Each working volume 2412 may further comprise a de-bounce thresholdlocated within each sub-volume threshold. For example, the first workingvolume 2412-1 may comprise a first de-bounce threshold 2415-1, and thesecond working volume 2412-2 may comprise a second de-bounce threshold2415-2. The second working volume may be activated once the sensorleaves the first de-bounce threshold and enters the second de-bouncethreshold. Similarly, the first working volume may be activated once thesensor leaves the second de-bounce threshold and enters the firstde-bounce threshold. Accordingly, the de-bounce thresholds may serve as“de-bouncing switches” for determining which working volume is to beactivated. The first de-bounce threshold 2415-1 may have a length L1″,and the second de-bounce threshold 2415-2 may have a length L2″. In someembodiments, the lengths L1″ and L2″ may be substantially the same. Inother embodiments, the lengths L1″ and L2″ may be different. The widthsof the first and second de-bounce thresholds may be the same, and theheights of the first and second de-bounce thresholds may be the same. Insome alternative embodiments (not shown), the widths of the first andsecond de-bounce thresholds may be different. Optionally, the heights ofthe first and second de-bounce thresholds may be different.

As shown in FIG. 24, the first and second working volumes may overlap soas to form a first overlapping working volume 2414-1 disposed at aboundary between the first and second subsets of field generator coils2404-1 and 2404-2. The first and second working volumes 2412-1 and2412-2 may overlap by various amounts. For example, the first and secondworking volumes 2412-1 and 2412-2 may overlap by 1%, 2%, 5%, 10%, 15%,20%, 25%, 30%, or more than 30%. The first and second working volumes2412-1 and 2412-2 may be configured to overlap such that a positionsensor can be accurately tracked and controlled near the boundaries ofthe control volumes 2412, and as a position sensor moves betweenadjacent working volumes 2412. The first overlapping working volume2414-1 may have a length U1, a width W, and a height H.

Each subset of field generator coils 2404 may comprise a number of fieldgenerator coils 2403. The number of field generator coils 2403 in thesubsets may be same or different. As shown in part B of FIG. 24, eachsubset of field generator coils 2404 may comprise eight field generatorcoils 2403. The field generator coils 2403 may be disposed along theedges of the surgical bed 2402 in two parallel rows 2406. The fieldgenerator coils 2403 may be spaced apart from one another along each row2406, at a pitch p in the Y-direction. Laterally opposite fieldgenerator coils 2403 in the two rows 2406 may be spaced apart by adistance d from each other in the X-direction. The field generator coils2403 in the subsets 2404 may be spaced in a configuration that allows anEM field of a predetermined strength to substantially extend over eachworking volume 2412.

6. Selective Activation of Field Generator Coils with One PositionSensor

FIG. 25 illustrates the selective activation of field generator coilsand working volumes as a surgical tool comprising a position sensormoves within an EM tracking surgical system, in accordance with someembodiments. Parts A, B, C, and D of FIG. 25 illustrate schematic topviews of a portion of an EM tracking surgical system 2500.

As shown in part A of FIG. 25, a position sensor 2516 may be disposed ata distal end of a surgical tool 2517. The surgical tools may includeendoscopes, catheters, ureteroscopes, or other similar devices.Initially, the surgical tool 2517 may be positioned such that theposition sensor 2516 is located at position A. Position A may be a pointwithin a first working volume 2512-1 above a first subset of fieldgenerator coils 2504-1. An EM system controller (e.g., EM systemcontroller 2508) may detect that the position sensor 2516 is within thefirst working volume 2512-1 and not in the second working volume 2512-2.Additionally, the EM system controller may detect that the positionsensor 2516 is within the first working volume 2512-1 but outside of afirst overlapping working volume 2514-1. The first overlapping workingvolume 2514-1 may be an overlapping region between the first and secondworking volumes 2512-1 and 2512-2. Accordingly, the EM system controllermay selectively activate the first subset of field generator coils2504-1 without activating the second subset of field generator coils2504-2. When the first subset of field generator coils 2504-1 isactivated, the first working volume 2512-1 may become an active workingvolume, as indicated by the shaded region over the first working volume2512-1.

During a surgical procedure, the surgical tool 2517 may move to adifferent location, such that the position sensor 2516 may move toposition B shown in part B of FIG. 25. Position B may be a point thatlies within the first working volume 2512-1 and the first overlappingworking volume 2514-1. Since position B lies near the boundary of thefirst working volume 2512-1, the EM system controller may activate thesecond subset of field generator coils 2504-2 in addition to the firstsubset of field generator coils 2504-1, to ensure that the positionsensor 2516 can be accurately tracked near the boundary between adjacentworking volumes 2512. When the first and second subset of fieldgenerator coils 2504-1 and 2504-2 are activated, the first and secondworking volumes 2512-1 and 2512-2 become active working volumes, asindicated by the shaded regions over the first and second workingvolumes 2512-1 and 2512-2.

Next, the surgical tool 2517 may move to a different location, such thatthe position sensor 2516 may move to position C shown in part C of FIG.25. Position C may be another point in the first overlapping workingvolume 2514-1. However, unlike position B, position C may lie within thesecond working volume 2512-2. Since position C lies near the boundary ofthe second working volume 2512-2, the EM system controller may continueto activate both the first and second subsets 2512, to ensure that theposition sensor 2516 can be accurately tracked near the boundary betweenadjacent working volumes 2512.

Next, the surgical tool 2517 may move to a different location, such thatthe position sensor 2516 may move to position D shown in part D of FIG.25. The EM system controller may detect that the position sensor 2516 iswithin the second working volume 2512-2 but outside of the firstoverlapping working volume 2514-1. Accordingly, the EM system controllermay continue to activate the second subset of field generator coils2504-2, but power off the first subset of field generator coils 2504-1.

7. Selective Activation of Field Generator Coils with a Plurality ofPosition Sensors

FIG. 26 illustrates selective activation of field generator coils andworking volumes as a surgical tool comprising a plurality of positionsensors moves within an EM tracking surgical system, in accordance withsome embodiments. Parts A, B, and C of FIG. 26 illustrate schematic topviews of a portion of an EM tracking surgical system 2600. Theembodiment of FIG. 26 has similarities to the embodiment of FIG. 25.

In FIG. 26, a surgical tool 2617 may be a flexible probe or shaftcapable of twisting and bending about different directions.Additionally, the surgical tool 2617 may comprise a plurality ofposition sensors 2616 that include position sensors 2616-1, 2616-2,2616-3, 2616-4, and 2616-5. For example, a position sensor 2616-1 may bedisposed at a distal end of the surgical tool 2617, and a plurality ofposition sensors 2616-2, 2616-3, 2616-4, and 2616-5 may be spaced apartalong a length of the surgical tool 2617. By placing the plurality ofposition sensors 2616 at different locations along the surgical tool2617, the position/orientation/shape of the surgical tool 2617 can bedetermined through use of an EM field, which may be important during asurgical procedure as the tool 2617 is being inserted into a patient'sbody. In some cases, the position/orientation/shape of the surgical tool2617 that is obtained by an EM system controller can be mapped onto thefluoroscopic image of the patient's body in real-time as the surgicalprocedure is being performed.

Additionally, in FIG. 26, more than two working volumes may be provided.For example, the EM tracking surgical system 2600 may comprise threeworking volumes 2612: a first working volume 2612-1, a second workingvolume 2612-2, and a third working volume 2612-3. In examples, 4, 5, 6,7, 8, 9, 10, or more than 10 working volumes 2612 may be provided.

As shown in part A of FIG. 26, the position sensors 2616-1, 2616-2,2616-3, 2616-4, and 2616-5 may be located at positions A1, A2, A3, A4,and A5, respectively. Positions A1, A2, and A3 may lie within the firstworking volume 2612-1 above a first subset of field generator coils2604-1. Positions A4 and A5 may lie outside of the first working volume2612-1 and/or any working volume. An EM system controller (e.g., EMsystem controller 2008 of FIG. 20) may detect that the position sensors2616-1, 2616-2, and 2616-3 are within the first working volume 2612-1,and not in the second and third working volumes 2612-2 and 2612-3.Additionally, the EM system controller may detect that the positionsensors 2616-1, 2616-2, and 2616-3 are within the first working volume2612-1 outside of a first overlapping working volume 2614-1.Accordingly, the EM system controller may selectively activate the firstsubset of field generator coils 2604-1 without activating the secondsubset of field generator coils 2604-2.

During a surgical procedure, the surgical tool 2617 may move from theposition shown in part A to the position shown in part B of FIG. 26.Referring to part B of FIG. 26, the position sensors 2616-1, 2616-2,2616-3, 2616-4, and 2616-5 may be located at positions B1, B2, B3, B4,and B5, respectively. Position B1 may be a point that lies within thesecond working volume 2612-2 outside of the first overlapping workingvolume 2614-1. Position B2 may be a point that lies within the secondworking volume 2612-2 and the first overlapping working volume 2614-1.Position B3 may be a point that lies within the first working volume2612-1 and the first overlapping working volume 2614-1. Positions B4 andB5 may be different points that lie within the first working volume2612-1 outside of the first overlapping working volume 2614-1.Accordingly, the EM system controller may activate the second subset offield generator coils 2604-2 in addition to the first subset of fieldgenerator coils 2604-1, to ensure that the position sensor 2616 can beaccurately tracked within the first and the second working volumes2612-1 and 2612-2.

Next, the surgical tool 2617 may move from the position shown in part Bto the position shown in part C of FIG. 26. Referring to part C of FIG.26, the position sensors 2616-1, 2616-2, 2616-3, 2616-4, and 2616-5 maybe located at positions C1, C2, C3, C4, and C5, respectively. PositionsC1 and C2 may be different points that lie within the third workingvolume 2612-3 outside of a second overlapping working volume 2614-2.Position C3 may be a point that lies within the third working volume2612-3 and the second overlapping working volume 2614-2. Positions C4and C5 may be different points that lie within the second working volume2612-2 outside of the second overlapping working volume 2614-2. None ofthe positions C1-C5 lies within the first working volume 2612-1 and/orthe first overlapping working volume 2614-1. Accordingly, the EM systemcontroller may activate the third subset of field generator coils 2604-3in addition to the second subset of field generator coils 2604-2, toensure that the position sensor 2616 can be accurately tracked withinthe second and the third working volumes. Additionally, the EM systemcontroller may power off the first subset of field generator coils2604-1 since none of the position sensors 2616 lies within the firstworking volume 2612-1.

Although FIG. 27 illustrates the tracking of a surgical tool having aplurality of position sensors, one of ordinary skill in the art wouldappreciate that the EM system can also be used to track a plurality ofsurgical tools having a plurality of position sensors. Each surgicaltool may have one or multiple position sensors.

8. EM Tracking Surgical Systems Having Reconfigurable Bed Portions

FIG. 27 illustrates schematic views of an EM tracking surgical systemhaving reconfigurable bed portions, in accordance with some embodiments.Part A of FIG. 27 illustrates a side view of a portion of a floating EMfield generator system 2700 when a surgical bed is in a first position.Part B of FIG. 27 illustrates the side view of the system 2700 when thesurgical bed is in a second position.

As shown in FIG. 27, a surgical bed 2702 may comprise reconfigurable bedportions that can move relative to each other. For example, the surgicalbed 2702 may comprise a first bed portion 2702-1 and a second bedportion 2702-2 connected at a hinge 2724 that allows the bed portions tomove (e.g., rotate and/or slide) relative to each other. A first subsetof field generator coils 2704-1 may be embedded along a length of afirst arm portion 2702-1. A second subset of field generator coils2704-2 may be embedded along a length of the second arm portion 2702-2.Accordingly, the first and second subsets of field generator coils 2704may be embedded along a length of arm portions that are adjacent to thesurgical bed 2702.

A first working volume 2712-1 may be defined above the first subset offield generator coils 2704-1, and a second working volume 2712-2 may bedefined above the second subset of field generator coils 2704-2, similarto the embodiment previously described in FIG. 24. In some embodiments,the dimensions and/or size of the first and second working volumes2712-1 and 2712-2 may be the same. Alternatively, the dimensions and/orsize of the first and second working volumes 2712-1 and 2712-2 may bedifferent.

As shown in FIG. 27, the first and second working volumes may overlap soas to form a first overlapping working volume 2714-1 disposed at aboundary between the first and second subsets of field generator coils2704-1 and 2704-2. The first and second working volumes 2712-1 and2712-2 may be configured to overlap by various amounts. For example, thefirst and second working volumes 2712-1 and 2712-2 may be configured tooverlap by 1%, 2%, 5%, 10%, 15%, 20%, 25%, 30%, or more than 30%. Thefirst and second working volumes 2712-1 and 2712-2 may be configured tooverlap such that one or more position sensors, such as position sensors2716 discussed above, can be accurately tracked and controlled near theboundaries of the control volumes 2712, and as the position sensor(s)2716 moves between adjacent working volumes 2712.

Each subset of field generator coils 2704 may comprise a number of fieldgenerator coils 2703. The number of field generator coils 2703 in thesubsets 2704 may be same or different. In FIG. 27, each subset of fieldgenerator coils 2704 may comprise eight field generator coils 2703, forexample similar to the embodiment previously described in FIG. 24. Thefield generator coils 2703 may be disposed along the edges of thesurgical bed 2702 in two parallel rows (not shown in FIG. 27). The fieldgenerator coils 2703 may be spaced apart from one another along each row(e.g., at a pitch p in the Y-direction). Laterally opposite fieldgenerator coils 2703 in the two rows may be spaced apart (e.g., by adistance d) from each other in the X-direction. The field generatorcoils 2703 in the subsets 2704 may be spaced in a configuration thatallows an EM field of a predetermined strength to substantially extendover each working volume 2712.

As shown in FIG. 27, a global coordinate system 2720 may be definedabove a center portion of the surgical bed 2702. For example, the globalcoordinate system 2720 may be defined above a boundary line between thefirst bed portion 2702-1 and the second bed portion 2702-2. An origin ofthe global coordinate system 2720 may lie above the center portion ofthe surgical bed 2702 along the Z-direction. The origin of the globalcoordinate system 2720 may also lie at a predetermined location abovethe hinge 2724 when the surgical bed is in the position shown in part Aof FIG. 27. The origin of the global coordinate system 2720 may serve asa datum point from which the positions of a patient's body, the subsetsof field generator coils 2704, and the working volume 2712 may bedefined.

A first local coordinate system 2722-1 may be defined above a centerportion of the first bed portion 2702-1. Likewise, a second localcoordinate system 2722-2 may be defined above a center portion of thesecond bed portion 2702-2. The first local coordinate system 2722-1 mayor may not have an origin that lies at a center portion of the firstworking volume 2712-1. Similarly, the second local coordinate system2722-2 may or may not have an origin that lies at a center portion ofthe second working volume 2712-2. For example, as shown in part A ofFIG. 27, the origin of the first local coordinate system 2722-1 may liebelow the center portion of the first working volume 2712-1, and inclose proximity to the first bed portion 2702-1. Likewise, the origin ofthe second local coordinate system 2722-2 may lie below the centerportion of the second working volume 2712-2, and in close proximity tothe second bed portion 2702-2.

Vectors may be defined between the global coordinate system 2720 and thelocal coordinate systems 2722-1 and 2722-2. For example, a vector T1 maybe defined from the origin of the first local coordinate system 2722-1to the origin to the global coordinate system 2720. A vector T2 may bedefined from the origin of the second local coordinate system 2722-2 tothe origin to the global coordinate system 2720. In some embodiments,another vector (not shown) may be defined from the origin of the firstlocal coordinate system 2722-1 to the origin of the second localcoordinate system 2722-2. The vectors T1 and T2 may be used to definethe spatial relationship between the first working volume 2712-1 and thesecond working volume 2712-2. In particular, the vectors T1 and T2 maybe used to define the spatial relationship between the first and secondworking volumes 2712-1 and 2712-2 relative to the datum point (origin ofthe global coordinate system 2720) as the first and second bed portions2702-1 and 2702-2 move relative to each other.

As shown in part A of FIG. 27, the first bed portion 2702-1 and thesecond bed portion 2702-2 may initially lie on a same horizontal planeextending along the Y-axis direction. The first and second bed portions2702-1 and 2702-2 may be configured to move relative to each other. Forexample, as shown in part B of FIG. 27, the first bed portion 2702-1 mayrotate by an angle θ in a clockwise direction about an X-axis extendingthrough the hinge 2724. The first bed portion 2702-1 may be rotated, forexample, to lower or raise a portion of a patient's body that issupported by the first bed portion 2702-1. Since the first controlvolume 2712-1 is defined by the EM field generated by the first subsetof field generator coils 2704-1, the first control volume 2712-1 mayalso rotate by the angle θ in a clockwise direction about the X-axis. Asshown in part B of FIG. 27, it may be observed that the origin of thefirst local coordinates system 2722-1 has shifted to a new location.Accordingly, a new vector T1′ may be defined from the shifted origin ofthe first local coordinates system 2722-1 to the origin of the globalcoordinates system 2720, whereby the vector T1′ is different from thevector T1. Since the second bed portion 2702-2 is not rotated relativeto the global coordinates system 2720, the origin of the second localcoordinates system 2722-2 remains unchanged, and therefore the vector T2remains the same. The vectors T1′ and T2 may be used to define thespatial relationship between the first and second working volumes 2712-1and 2712-2 relative to the datum point (origin of the global coordinatesystem 2720) after the first bed portion 2702-1 has moved relative tothe second bed portion 2702-2.

Although part B of FIG. 27 illustrates movement of the first bed portion2702-1 relative to the second bed portion 2702-2, the movement betweenthe bed portions is not limited thereto. For example, in someembodiments, the second bed portion 2702-2 may move relative to thefirst bed portion 2702-1. Optionally, the first and second bed portions2702-1 and 2702-2 may simultaneously move relative to each other suchthat the origins of the first and second local coordinate systems shiftto different locations. The relative movement between the bed portions2702-1 and 2702-2 may comprise a rotational motion, a translationalmotion, and/or a combination of rotational and translational motion,about one or more axes. Accordingly, relative movement of the bedportions 2702-1 and 2702-2 in one or more degrees of freedom (e.g., sixdegrees of freedom) may be contemplated.

In some embodiments, a position, shape, and/or size of the overlappingworking volume 2714 between adjacent working volumes may change when thebed portions move relative to each other. For example, as shown in partA of FIG. 27, a center (or centroid) of the first overlapping workingvolume 2714-1 may be located at the origin of the global coordinatessystem 2720. The first overlapping working volume 2714-1 may have aregular shape (e.g., defined by a length U1, width W, and height H,similar to the embodiment previously shown in FIG. 24).

When the first bed portion 2702-1 rotates relative to the second bedportion 2702-2, the position, shape, and/or size of the firstoverlapping working volume 2714-1 may change. For example, as shown inpart B of FIG. 27, the first overlapping working volume 2714-1 maytransform to overlapping working volume 2714-1′ having an irregularshape (e.g., having a trapezoidal-like profile as viewed from a side ofthe overlapping working volume 2714-1′). The origin of the globalcoordinates system 2720 remains unchanged by the relative rotation ofthe bed portions. Unlike part A of FIG. 27, the center (or centroid) ofthe overlapping working volume 2714-1′ is not located at the origin ofthe global coordinates system 2720 after the rotation. Instead, thecenter (or centroid) of the overlapping working volume 2714-1′ may beoffset from the origin of the global coordinates system 2720 by a vectorT3 after the rotation.

FIGS. 28A and 28B illustrate sizing of a reconfigurable bed portion ofan EM tracking surgical system based on exemplary dimensions of a humantorso, in accordance with some embodiments. FIG. 28A illustratesexemplary dimensions of a human torso and a working volume that isdefined based on those exemplary dimensions. FIG. 28B illustrates aschematic view of a patient who is placed on a reconfigurable bedportion of an EM tracking surgical system.

FIG. 28A illustrates exemplary dimensions of a human torso. For example,a length of a longest human torso (as measured from neck to anus) may beabout 32.9 inches, and a width of the human torso may be about 13inches. A working volume of each subset of field generator coils may bedefined based on those dimensions.

As shown in FIG. 28B, the first bed portion 2802-1 may be rotatedrelative to the second bed portion 2802-2, such that the patient's bodyis rotated an angle θ relative to a longitudinal axis Y1 extendinglongitudinally along the second bed portion 2802-2.

A first working volume 2812-1 and a second working volume 2812-2 may beassociated with the first subset of field generator coils 2804-1 and thesecond subset of field generator coils 2804-2, respectively. In someembodiments, the first working volume 2812-1 may be a cylinder. Thediameter of the cylinder may be about 5″, 6″, 7″, 8″, 9″, 10″, 11″, 12″,13″, 14″, 15″, 16″ 17″, 18″, 19″, 20″, 21″, 22″, 23″, 24″, 25″, orgreater than 25″. The height of the cylinder may be about 5″, 6″, 7″,8″, 9″, 10″, 11″, 12″, 13″, 14″, 15″, 16″ 17″, 18″, 19″, 20″, 21″, 22″,23″, 24″, 25″, or greater than 25″. In some examples, a cylinder mayhave a minimum diameter and height of about 5″×5″. In other examples, acylinder may have a maximum distance and height of about 25″×25″.Optionally, in some examples, each of the diameter and height of acylinder may be less than 5″, or greater than 25″. Optionally, the firstworking volume 2812-1 may be a cuboid. The length of the cuboid may beabout 5″, 6″, 7″, 8″, 9″, 10″, 11″, 12″, 13″, 14″, 15″, 16″ 17″, 18″,19″, 20″, 21″, 22″, 23″, 24″, 25″, or greater than 25″. The width of thecuboid may be about 5″, 6″, 7″, 8″, 9″, 10″, 11″, 12″, 13″, 14″, 15″,16″ 17″, 18″, 19″, 20″, 21″, 22″, 23″, 24″, 25″, or greater than 25″.The height of the cuboid may be about 5″, 6″, 7″, 8″, 9″, 10″, 11″, 12″,13″, 14″, 15″, 16″ 17″, 18″, 19″, 20″, 21″, 22″, 23″, 24″, 25″ orgreater than 25″. In some examples, a cuboid may have a minimum length,width, and height of about 5″×5″×5″. In other examples, a cuboid mayhave a maximum length, width, and height of about 25″×25″×25″.Optionally, in some examples, each of the length, width, and height of acuboid may be less than 5″, or greater than 25″. The second workingvolume 2812-2 may or may not have the same shape and/or dimensions asthe first working volume 2812-1. Any shape and/or dimensions for thefirst and second working volumes may be contemplated.

As shown in FIG. 28B, a fluoroscopic imaging system 2828 may be placedabove the patient's body. For example, the fluoroscopic imaging system2828 may be placed within or above the second working volume 2812-2. Thefluoroscopic imaging system 2828 may be supported by a mechanical arm2828-1 extending towards and/or over the first bed portion 2802-1. Inthe example of FIG. 28B, the fluoroscopic imaging system 2828 may beused to capture fluoroscopic images of the patient's body within thesecond working volume 2812-2. Since the second subset of field generatorcoils 2804-2 is placed within arms that are adjacent to the second bedportion 2802-2, a central portion of the surgical bed may be free enoughof effects from the field generates such that fluoroscopy can be usedwith little or no obstruction.

FIG. 29 illustrates a reconfigurable bed portion of an EM trackingsurgical system, in accordance with some embodiments. As previouslydescribed in FIGS. 28A, and 28B, a surgical bed 2902 may comprise afirst bed portion 2902-1 and a second bed portion 2902-2 that may bedisposed on a base 2905. The first bed portion 2902-1 may be operablyconnected to a hinge 2924 that allows the first bed portion 2902-1 tomove (e.g., rotate and/or translate) relative to the second bed portion2902-2.

As shown in FIG. 29, a first bed portion 2902-1 may have a length l anda width w. In some embodiments, the length l may be about 29.5 inches,and the width w may be about 18.5 inches. In some embodiments, a cutout2930 may be formed at an end of first bed portion 2902-1, so as toprevent mechanical interference as the first bed portion 2902-1 movesrelative to the second bed portion 2902-2. In the example of FIG. 29,the cutout 2930 may have a trapezoidal shape, and may be offset by adistances from an edge portion of the first bed portion 2902-1.

The first bed portion 2902-1 may further include two arms 2906 that areadjacent to the surgical bed. As previously described, by placing aplurality of field generator coils within arms 2906 adjacent to thesurgical bed 2902 (e.g., the first bed portion 2902-1), unobstructed useof fluoroscopy can be achieved to image at least a portion of apatient's body. Each row 2906 may have a width of t that is associatedwith an area of fluoro obstruction. In some embodiments, the width t maybe less than or equal to about 2 inches. It should be noted that rows2906 constitute areas of fluoroscopy obstruction, since the fieldgenerator coils are radio-opaque.

FIG. 30 illustrates the dimensions and locations of field generatorcoils on a reconfigurable bed portion of an EM tracking surgical system,in accordance with some embodiments. In the example of FIG. 30, areconfigurable bed portion 3002-1 of a surgical bed may have a length l′and a width w′. In some embodiments, the length 1′ may be about 18.1inches, and the width w′ may be about 21.8 inches.

The bed portion 3002-1 may further include two parallel rows 3006 on itsedges. In examples, the two parallel rows may comprise arms that areadjacent to the surgical bed. The arms may be decoupled from thesurgical bed such that weight of a patient that bends a surgical bed maynot adversely affect the placement of field generator coils within armsadjacent to the surgical bed. As previously described, by placing aplurality of field generator coils along two arms adjacent to thesurgical bed, unobstructed use of fluoroscopy can be achieved to imageat least a portion of a patient's body. Each row 3006 may have a widthof t′. In some embodiments, the width t′ may be less than or equal toabout 3.025 inches. The two parallel rows 3006 may be separated by adistance wl. In some embodiments, the distance wl may be about 15.75inches. Additionally, rows 3006 may constitute areas of fluoroscopyobstruction, since the field generator coils are radio-opaque.

As shown in FIG. 30, end portions 3015 of the bed portion 3002-1 maycorrespond to regions where adjacent working volumes overlap. The endportions 114 may be separated by a distance U2. In some embodiments, thedistance U2 may be about 14.5 inches.

FIG. 31 illustrates an estimated length of a working volume based on thedimensions of a reconfigurable bed portion of an EM tracking surgicalsystem, in accordance with some embodiments. As shown in FIG. 31, adistance from an edge of a hinge bearing 3124 to an edge of a cutout3130 of a first bed portion 3102-1 may be denoted by l1. The distance l1may be indicative of a length of a total working volume above the firstbed portion 3102-1. In some embodiments, the distance l1 may be about26.5 inches. FIG. 31 also illustrates first bed portion 3102-1 angledwith respect to second bed portion 3102-2.

FIG. 32 illustrates an exemplary working volume above a reconfigurablebed portion of an EM tracking surgical system, in accordance with someembodiments. As shown in FIG. 32, a total working volume 3212 may bedefined above a first bed portion 3202-1 of a surgical bed 3202. In FIG.32, first bed portion 3202-1 is shown angled with respect to second bedportion 3202-2. The total working volume 3212 may comprise a firstworking volume 3212-1 and a second working volume 3212-2. The totalworking volume 3212 may have a length L_(T), a width W, and a height H.In some embodiments, the length LT may be about 31 inches, the width Wmay be about 19 inches, and the height H may be about 19.7 inches. Itshould be noted that the invention is not limited thereto, and that anydimensions of the total working volume may be contemplated. Aspreviously described, the first working volume 3212-1 and the secondworking volume 3212-2 may overlap, which can help to minimize deadzones(places where a position sensor cannot be tracked, either due to a weakEM field or EM interference).

As used herein A and/or B encompasses one or more of A or B, andcombinations thereof such as A and B. It will be understood thatalthough the terms “first,” “second,” “third” etc. may be used herein todescribe various elements, components, regions and/or sections, theseelements, components, regions and/or sections should not be limited bythese terms. These terms are merely used to distinguish one element,component, region or section from another element, component, region orsection. Thus, a first element, component, region or section discussedbelow could be termed a second element, component, region or sectionwithout departing from the teachings of the present invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including,” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components and/or groupsthereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top” may be used herein to describe one element's relationship to otherelements as illustrated in the figures. It will be understood thatrelative terms are intended to encompass different orientations of theelements in addition to the orientation depicted in the figures. Forexample, if the element in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on the “upper” side of the other elements. The exemplary term“lower” can, therefore, encompass both an orientation of “lower” and“upper,” depending upon the particular orientation of the figure.Similarly, if the element in one of the figures were turned over,elements described as “below” or “beneath” other elements would then beoriented “above” the other elements. The exemplary terms “below” or“beneath” can, therefore, encompass both an orientation of above andbelow.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. Numerous differentcombinations of embodiments described herein are possible, and suchcombinations are considered part of the present disclosure. In addition,all features discussed in connection with any one embodiment herein canbe readily adapted for use in other embodiments herein. It is intendedthat the following claims define the scope of the invention and thatmethods and structures within the scope of these claims and theirequivalents be covered thereby.

What is claimed is:
 1. A floating electromagnetic field generatorsystem, comprising: a base; a surgical bed platform supported by thebase and configured to directly support a patient, the surgical bedplatform includes a first bed portion and a second bed portion, thefirst bed portion being movable relative to the first bed portion; abrace disposed within the surgical bed platform and directly connectedto the surgical bed platform; first and second bed rails attached to thesurgical bed platform on opposing sides of the surgical bed platform; afirst arm that is directly attached to the brace, the first armpositioned directly between the surgical bed platform and the first bedrail, the first arm includes a first arm portion, a second arm portion,and a hinge connecting the first arm portion and the second arm portion,the first arm portion having a first field generator coil connectedthereto, the second arm portion having a second field generator coilconnected thereto, the first arm portion configured to rotate about thehinge relative to the first bed portion; and a second arm that isdirectly attached to the brace, the second arm positioned directlybetween the surgical bed platform and the second bed rail, and thesecond arm having at least one field generator coil embedded therein,the second arm positioned parallel to the first arm, wherein the bracemaintains relative position between the first arm and the second arm asthe first arm is displaced.
 2. The system of claim 1, wherein the braceis a circular brace.
 3. The system of claim 1, wherein the first arm andthe second arm are configured to stay rigid independent of movement ofthe surgical bed platform due to a weight of the patient.
 4. The systemof claim 3, wherein the first arm and the second arm are configured tostay rigid independent of bending of the surgical bed platform due tothe weight of the patient.
 5. The system of claim 1, the first arm andthe second arm are attached to the brace using a brace hinge.
 6. Thesystem of claim 1, wherein the first and the second arm are additionallyattached using a connecting component.
 7. The system of claim 6, whereinthe connecting component is a base connecting component comprising anintermediate brace.
 8. The system of claim 7, wherein the intermediatebrace has a width between three inches and five inches.
 9. The system ofclaim 1, wherein the brace is configured to prevent movement of thefirst arm and the second arm due to movement of the surgical bedplatform caused by a weight of the patient.
 10. A system, comprising: afirst surgical bed platform that is connected to, and movable withrespect to, a second surgical bed platform, the first surgical bedplatform and the second surgical bed platform configured to support apatient thereon, the first surgical bed platform configured to rotaterelative to a longitudinal axis of the second surgical bed platformalong a plane defined by the second surgical bed platform to move aposition of the patient; a brace connected to the first surgical bedplatform; first and second bed rails attached to the first surgical bedplatform on opposing sides of the first surgical bed platform; a firstarm that is directly attached to the brace, the first arm positioneddirectly between the first surgical bed platform and the first bed rail,and the first arm having at least one field generator coil connectedthereto, wherein the first arm includes a first portion, a secondportion, and a hinge connecting the first portion and the secondportion, the first portion having a first field generator coil connectedthereto, the second portion having a second field generator coilconnected thereto, the first portion configured to rotate about thehinge relative to the first surgical bed platform; and a second arm thatis directly attached to the brace, the second arm positioned directlybetween the first surgical bed platform and the second bed rail, and thesecond arm having the at least one field generator coil connectedthereto, wherein the brace maintains relative position between the firstarm and the second arm as at least one of the first arm or the secondarm is displaced.
 11. The system of claim 10, wherein: the first arm andthe second arm are configured to stay rigid independent of movement ofthe first surgical bed platform due to a weight of the patient, and thefirst arm and the second arm are configured to stay rigid independent ofbending of the first surgical bed platform due to the weight of thepatient.
 12. The system of claim 10, wherein each of the first arm andthe second arm have a plurality of field generator coils connectedthereto.
 13. The system of claim 10, wherein each of the first arm andthe second arm have a plurality of field generator coils detachablyattached thereto.
 14. The system of claim 10, wherein each of the firstarm and the second arm have a plurality of field generator coilsembedded within.
 15. The system of claim 10, wherein the first arm ishingedly attached to the brace and structurally supported by the brace.16. The system of claim 10, wherein the brace is configured to preventmovement of the first arm and the second arm due to movement of thefirst surgical bed platform caused by a weight of the patient.
 17. Asystem, comprising: a base; a surgical bed platform supported by thebase and configured to, in use, support a patient resting thereon, thesurgical bed platform includes a first bed portion and a second bedportion, the second bed portion being movable relative to the first bedportion; a brace disposed within the surgical bed platform and directlyconnected to the surgical bed platform; first and second bed railsattached to the surgical bed platform on opposing sides of the surgicalbed platform; a first hinged arm directly attached to the brace, thefirst hinged arm positioned directly between the surgical bed platformand the first bed rail, the first hinged arm includes a first armportion, a second arm portion, and a hinge connecting the first armportion and the second arm portion, the first arm portion having a firstfield generator coil connected thereto, the second arm portion having asecond field generator coil connected thereto, the first arm portionconfigured to rotate about the hinge relative to the second bed portion;a second hinged arm directly attached to the brace, the second hingedarm positioned directly between the surgical bed platform and the secondbed rail, and the second hinged arm having at least one field generatorcoil embedded therein, the second hinged arm positioned parallel to thefirst hinged arm; and a base connecting component that connects thefirst hinged arm and the second hinged arm, wherein the first hinged armand the second hinged arm are independent from weight-bearing portionsof the surgical bed platform.
 18. The system of claim 17, wherein thebase connecting component is at a level of the surgical bed platform.19. The system of claim 17, wherein the base connecting component isbelow the surgical bed platform.
 20. The system of claim 17, wherein thefirst hinged arm and the second hinged arm are configured to stay rigidindependent of movement and bending of the surgical bed platform due toa weight of the patient.